A conventional heat sink is disclosed in patent document 1. In this heat sink, a power device, such as a semiconductor chip, etc. is mounted on at least one face, and heat from the power device is radiated by a cooling medium circulated within a refrigerant flow path arranged in the interior.
This heat sink has two surface plates and a laminating body in which plural flow path plates are laminated and the laminating body is laminated together with the surface plate.
The plural flow path plates constituting the laminating body are formed in a plate shape in which a through hole is press-punch-processed within a flat joining face. Each of these flow path plates is laminated by each joining face so that a flow path communicated in a laminating direction is formed within the laminating body while each through hole is meandered and extended in parallel with the joining face, and plural columns are formed within the joining face.
One set or plural sets of flow-in holes and flow-out holes communicated with the flow path of the laminating body in the laminating direction are formed on at least one side of the surface plate. Piping is connected to each of the flow-in hole and the flow-out hole. A flow-in path is formed by the piping and the flow-in hole. A flow-out path is formed by the piping and the flow-out hole.
Thus, in this heat sink, the refrigerant flow path is constructed by the flow-in path, the flow path and the flow-out path.
In the conventional heat sink having such a construction, the power device is mounted to at least one side of the surface plate, and is set to a power module. In the heat sink for the power module, the cooling medium is flowed into the flow path from the piping through the flow-in hole, and is flowed out of the piping through the flow-out hole. In the meantime, the cooling medium radiates heat from the power device. The flowed-out cooling medium is cooled by a radiator, etc., and is then circulated.    Patent document 1: JP-A-2-306097